Background: Malignancy is the second most common cause of death in renal transplant patients with functioning graft and its incidence increases with time after organ transplantation.
Objective: To present the cumulative incidence and manifestations of malignancy among renal transplant recipients in Phramongkutklao hospital between 1987 and 2009.
Material and Method: To retrospectively review of the transplant charts and records of 168 kidney transplant recipients from October 1, 1987 to November 15, 2009 at Phramongkutklao Hospital. The data related to malignancy were recorded.
Results: The cumulative incidence of malignancy was 4/168 (2.4%) recipients with a median age of 45 years (range, 8-55 years). The median time of diagnosis of malignancy after transplantation was 7.3 years (range, 0.8-10.4 years). All four patients had posttransplantation malignancy. The diagnosis was based on pathological specimens. All of them received cyclosporine, prednisolone and azathioprine or mycophenolate mofetil as immunosuppressive regimen. Two patients had native renal cell carcinoma (RCC), one had post transplant lymphoproliferative disorder (PTLD), the other had a malignant hemangiopericytoma. Two patients (PTLD and advanced RCC cases) are alive, one patient died of malignancy (malignant hemangiopericytoma) and the other died of infection (Pseudallescheria boydii brain abscess).
Conclusion: The incidence of malignancies in the present study was increased among renal transplant recipients compared to the general population especially renal cell carcinoma. Because of the higher risk to develop malignancy in transplant recipients, a close surveillance for early detection of malignancy is necessary in the long term follow-up.

Keywords: Malignancy, Renal cell carcinoma (RCC), Post-transplant lymphoproliferative disorder (PTLD), Transplant